Water Sweating For Airlines

The air in contact with the surface of the lines has reached its dew point.

Dew point

The line is cold...

One reason could be that most pneumatic systems use refrigerated dryers. The air is cooled to condense the moisture out. This cool air passing through the lines will drop the temperature of the lines so that moisture is condense out of the ambient air around the line on to them.

Have a air motor here that with it's close proximity to the dryer and volume. When it exhausts during the summer it looks like it smoking. The cool air instantly condense the moisture in the air to a fog.

I would think that since your title says airlines they would use desiccant type dryers. Space and weight being factors. So it maybe an elevation issue air at 20 thousand feet will be much colder then at ground level. If the receiver is of any size it may store the cold air through changes of elevation.

What this pneumatic cylinder on? Thought most airplanes used hydraulic controls.

I read the title as "Water Sweating For Air Lines", after my initial confusion.??

That maybe what he meant but not what he wrote.

Well I cover some of the possibilities for both if not.

Now you know my confusion asking for use of pneumatics in an airplane.